Method and apparatus for continuously refining or improving mineral oils by means of a solid adsorbent



961 D. E. A. JANCHEN 7 METHOD AND APPARATUS FOR CONTINUOUSLY REFINING onIMPROVING MINERAL OILS BY MEANS OF A SOLID ADSORBENT Filed July 29, 19575 Sheets-Sheet 1 REfl-WERAUOA Z ONE CHARGE 0/L I 80L VENT NAAELP RFCYCLE24 DISTRIBUTOR FROM/C 7' 19900167 Ar-foR/sys Oct. 10, 1961 D. E. A.JANCHEN 3,003,927

METHOD AND APPARATUS FOR CONTINUOUSLY REFINING 0R IMPROVING MINERAL OILSBY MEANS OF A SOLID ADSORBENT Filed July 29, 1957 3 Sheets-Sheet 2idllllllll.

V 0 I l l l l lnnm h I m n e In a 0. M 5 n 18 a W n. s PUQIM VW t T 4 76 7 Q Oct. 10, 1961 D. E. A. JKNCHEN 3,003,927

METHOD 'AND APPARATUS FOR CONTINUOUSLY REFINING OR IMPROVING MINERALOILS BY MEANS OF A SOLID ADSORBENT 3 Sheets-Sheet 3 Filed July 29. 1957r w m. V

,4 1-1-0 R'ME ys 3,003,927 Patented Oct. 10, 1961 ice 3,003,927 METHODAND APPARATUS FOR CONTINUOUSLY REFINING R MPROVHNG MINERAL OILS BY MEANSOF A SOLID ADSDRBENT Dieter Ernst August Jiinchen, Neu-Allschwil,Switzerland, assignor to Carnag @hemieerzeugnisse und AdsorptionstechnikA.G., Basel, Switzerland Filed July 29, 1957, Ser. No. 674,826 Claimspriority, application Germany Sept. 4, 1956 2 Claims. (Cl. 196-46) Thepresent invention relates to a method and apparatus for continuouslyrefining or improving mineral oils by means of a solid adsorbent, andmore particularly, by moving the oil and a granular adsorbent in acountercurrent relative to each other and by thus bringing them intointimate contact with each other.

The method according to the present invention is especially adapted forrefining or improving mineral oils, for example, crude distillateshaving a boiling point of more than 550 F., similar semirefinedproducts, as well as distillation residues and used insulating orlubricating oils, by means of a solid granular adsorbent, preferablyaluminum oxide. The adsorbent then adsorbs the undesired ingredients ofthe oils so that one or more final products will be attained whichdiffer in their degree of refinement.

The known methods of treating mineral oils by means of solid adsorbentsfor refining or purifying purposes were carried out either by a fixedbed percolation or according to the countercurrent principle. The fixedbed percolation has a series of well-known serious disadvantages. Sincesuch method does not operate continuously, a large number of adsorptioncontainers are required, some of which are not being used in theoperation at any particular time. Furthermore, the quality of theproducts attained varies very considerably in accordance with the changein condition of the adsorbent from time to time. For this reason, manyattempts have been made to move liquid oil and solids adsorbents in acountercurrent relative to each other in order to attain a reallycontinuous operation. In one known apparatus, the solids were treatedlike a liquid and conducted in a continuous current in a downwarddirection through the liquid by means of gravity, although means had tobe provided to loosen up the solids. Such loosening had the disadvantagethat it considerably reduced the effectiveness of the adsorbent sincethe filtering effect thereof was lost. Furthermore, due to suchloosening, the main advantage of the application of the countercurrentprinciple was also lost, namely, that the fresh uncharged adsorbent willalways come into contact with the liquid which is already considerablyrefined, while the adsorbent which is already extensively charged withimpurities will act upon the liquid which still contains all impurities.

Another known method which avoids the above-mentioned disadvantages to aconsiderable extent is used for refining or improving mineral oils andoperates substan tially as follows:

The oil to be treated is pumped in an upward direction through a vesselwhich has a sieve plate near its bottom. The sieve plate supports alayer of adsorbent, particularly a prepared clay, through which the oilis forced under pressure. The finally treated oil is then withdrawn fromthe upper area of the vessel. The adsorbent is replenished from above,while the used-up adsorbent is withdrawn from the lower part of thepiled layer through pipes. The adsorbent which still contains aconsiderable proportion of oil is then washed out by means of alow-boiling solvent in a washing apparatus which operates substantiallyin accordance with the same principle as the adsorption apparatus. Thewashed oil is then passed to a stripper and is thereafter returned tothe adsorption stage. The adsorbent is dried, which means that theadhering solvent is driven off by being heated indirectly, and theadsorbent is then regenerated in a special regenerating furnace by beingheated to a temperature of 900 to 1400" F., whereupon after beingreplenished with fresh adsorbent it returns to the adsorption stage.

Although better than the first-mentioned method, this last method stillhas a series of serious disadvantages. The continuous countercurrentengagement between the oil and the adsorbent is made possible by forcingthe granular adsorbent, which, similar to a heavy liquid, is conductedby gravity to move in the opposite direction to the oil, both toward andaway from the container through relatively narrow pipes. Since pipes arenot very well adapted to convey solid materials, the operation of anapparatus of this type is at least to some extent subject to breakdowns.The feeding of the solid adsorbent as if it were a liquid also subjectsthe same to considerable mechanical abrasion in that it will be groundto a smaller granular size which, in turn, impairs the ability of theoil to pass therethrough.

By fixing the quantitative relationship between the flow of adsorbentand the flow of oil to a definite value, it is also possible todetermine the quality of the one final product. However, the mentionedmethod does by no means permit the simultaneous production of oils ofdifferent quality and therefore also not the most favorable utilizationof the adsorbent, as will be further explained below.

It is therefore an object of the present invention to provide acontinuously operating method and apparatus for refining mineral oils bybringing about a reciprocal action of granular solids and mineral oilsrelative to each other in a countercurrent flow, and in a manner so asto overcome the disadvantages of the methods and apparatus previouslyknown.

A further object of the present invention is to provide a continuousmethod of the mentioned type, particularly for refining mineral oils bymeans of a solid adsorbent, wherein the solids are brought into acountercurrent contact with the oil in such a manner that the adsorbentwill be conveyed from below in an upward direction and the oil fromabove in a downward direction.

Another object of the present invention consists in applying only suchconveying means for moving the solid adsorbent which insure such flow tobe always free of any difiiculty or complications.

A further object of the present invention is to provide a refiningmethod which permits more than one kind of oil to be produced in oneapparatus to that the adsorbent will be more fully utilized than inprevious methods.

Another object of the present invention is to provide a new apparatusfor carrying out the mentioned method.

Further objects, features, and advantages of the present invention willbe apparent from the following detailed description of one preferredembodiment thereof, particularly when read with the reference tothe-accompanying drawings, in which- FIG. 1 shows a diagrammaticillustration of the course of the different proceedings of the methodaccording to the invention;

FIG. 2 shows a diagrammatic view of an apparatus for carrying out themethod according to the invention within the adsorption zone;

FIG. 3 shows a side view of the apparatus according to FIG. 2, turnedthereto about an angle of FIG. 4 shows a side view of a container usedaccording to the invention for transporting the solid granular material;I I l i FIG. 5 shows a vertical cross section through the containerillustrated in FIG. 4;

FIG. 6 shows a plan viewof a modification of the container; while 1 FIG.7 shows a cross section taken along line 77 of FIG. 6.

Referring to the drawings, the adsorption zone of the apparatusaccording to the invention contains several superimposed containers 1,each of which contains a layer of granular adsorbent of equal heightsupported on a sieve plate. The liquid to be treated, for example, oil,which is fed from above into the respective uppermost container 1 flowsby gravity downwardly and successively through all the superimposedfilter containers 1 disposed within the adsorption zone. The oil in itsfinally prepared form emerges from the lowest container 1 and is thenpassed through a distributor 24 to storage tanks A and B, as will besubsequently described in greater detail.

The respective uppermost container 1, the adsorbent in which is used toa greater extent than that in the lower containers is from time to timeremoved from the adsorption zone. All the other containers are thenmoved upwardly at the same time by means of an elevating mechanismindicated diagrammatically in FIG. 1, so that each individual container1 then assumes the place which was previously taken up by the containerabove it, while a new container 1 with fresh adsorbent is inserted atthe lower end of the adsorption zone. At this time, the fiow of oilemerging from the new lowest container 1 is temporarily interruptedsince it first has to be charged with oil before it can again flow outof this container. The oil which then at first emerges from the lowestcontainer has a very high degree of refinement and one considerablyabove that of the main body of oil which emerges subsequently. Arelatively small quantity of this big ly refined oil is then passed tothe storage tank A by means of the distributor 24, the operation ofwhich may be timecontrolled just as the supply of adsorbent. When thedegree of refinement decreases because the adsorbent in the lowestcontainer 1 becomes more and more charged with impurities, the mainquantity of filtered oil will be conducted to storage tank B.

A special advantage of the method according to the present invention isthe fact that the treated oil may thus be subdivided. The quality of themain body of oil which is determined by thev rate of flow of oilrelative to the adsorbent does not become noticeably worse after thehighly refined oil has been withdrawn from the main body at thebeginning of the operation (also see the following Table III).

In order to permit the oil to percolate at sufiicient speed through theplurality layers of adsorbent in the superimposed containers 1, it isnecessary to maintain the viscosity of the oil within the adsorptionzone below 20 cst. and preferably between 5 and cst. The viscosity ofmore highly viscous oils may be reduced by an addition of a neutralsolvent, for example, petroleum ether. However, the preferred manner ofreducing the viscosity consists in increasing the temperature of the oilWithin the adsorption zone.

After the container 1 with the spent adsorbent has been removed from theupper end of the adsorption zone, it is moved to the washing zone 25which operates according to the same principle as the adsorption zone.In this washing zone, the oil adhering to the adsorbent is washed out bymeans of a suitable solvent, preferably gasoline, petroleum ether, orthe like, whereupon the solution is conducted to a stripper 2.6. Thesolvent then returns from the upper part of the stripper 26 to thewashing zone 25, while the oil which has been washed out is returnedfrom the bottom of stripper 26 to the adsorption zone. The washing ofthe adsorbent is carried out only to such an extent that the undesirablefirmly adsorbed impurities will remain on the adsorbent.

The adsorbent is then freed from the adhering solvent by being heated ina drier 27. Insofar as the present invention is concerned, it is of noconsequence whether the adsorbent is washed and thereafter alsoregenerated within the portable container 1 or whether it is removedfrom the container and moved through drier 27 and the regeneratingfurnace 28 by some other conveying means. However, it constitutes adefinite advantage that it is possible according to the invention toretain the adsorbent within its container 1 during the entire cyclicprocess.

In the regenerating furnace 28 which may be of any suitableconstruction, for example, a revolving cylindrical furnace or the like,the impurities of an organic nature which are adsorbed on the adsorbentare burned oif so that the adsorbent will thus be regenerated. If theproportion of organic substances amounts to at least 1.5 percent byweight of the adsorbent, it will not be necessary to add a fuel orexternal heat. The intensity of the washing process in the washing zone25 should therefore be limited to arrive at such proportion.

The adsorbent will thereafter return from the regenerating furnace 28 tothe adsorption zone, possibly after being repenlished with freshadsorbent.

The adsorbent for carrying out the method according to the inventionpreferably consists of gamma aluminum oxide of a grain size of 0.02 to0.2 mm., and preferably of 0.06 to 0.15 mm. Such adsorbent has a seriesof advantages over the natural or synthetic clays as conventionallyused. Among these advantages is the fact that the regeneration may becarried out very easily since the aluminum oxide has a greater thermalresistance than clays. It is thus possible to carry out the regenerationat temperatures of 900 to l600 F. which may be done without anycomplicated and expensive cooling devices within the regenerationfurnace. Even if the adsorbent should termporarily absorb moisture, thiswill also not cause any irreparable damage.

However, the method according to the invention is not restricted to theuse of aluminum oxide but may also be carried out by means of otheradsorbents, such as clays or silicates.

The oils which are suitable for being refined according to the newmethod are viscous mineral oils of any kind such as, for example, crudedistillates having a boiling point above 550 F., semirefined oils, andresidues, as well as used technical oils such as insulating oils andlubricating oils including used lubricating oils of internal combustionengines.

The following Table I illustrates the eificiency of the new method inthe production of two different oils, as well as the operating datawithin the adsorption zone. Oil A is the semirefined, acid-treatedproduct of an oil from the Middle East, while oil B is a correspondingcrude distillate.

Table I Operating Data (Ads-Zone) A B Adslo/iihgntzAlgminaz 0 tomranular, Size (mm.) 0.09 0.09 Apparent Density, (gJemfi) 0. 89 0.80Temperature, C.) 80 Actual Viscosity of Oil (cst.) 8. 5 8. 5

Flow Velocity (mL/cmflh.) 8. 7 8. 4

Ratio: Volume Product Oil/Volume Adsorbent. 3.0 3. 0

Oil Data Product Chargv Product Charge Color (N.P.A.) 1 2 Q 2 Viscosity(cst.): 4+

20: C 81 83 103. 5 113 50 20 21 22. 4 22. 3 Dgjul5lfic8l2l0fl Number,LP.

55 120 300 210 30 Oxidation Test (After 3 days 0 C. with copper strip):

Saponification Value 0.1 0. 3 0. l 0. 3 Sludge 0. 005 0. 03 0. 005 0.03

senses? Table II illustrates the efiiciency of the new method in theproduction of two diiferent lubricating oils of internal combustionengines. Oil C is a distillate of such a used oil, while oil D is a usedlubricating oil of internal combustion engines which has not beenpretreated.

Table III finally shows how a small quantity of very pure product oilmay be produced according to the invention aside from the less refinedmain quantity of product oil without any noticeable unfavorableinfluence upon the quality of the main quantity. This is the same kindof oil as identified with C in Table II.

Table III Ratio: Volume Product Oil/ 0-0.2 0.2-3.0 0.3.0

Volume Adsorbent Color N.P.A Water White 2 2 Density (g./!I1l.) 0.860 0.873 0.875 Refractive Inde 1.4740 1. 4830 1. 4832 V' cos't cst.

ls 20 lim 81.0 I04. 5 104.4 50 C 21.2 24. 7 24. 7 Steam EmulsificationNumber, 30 60 60 AS'IM D. 157-36. Saponification Number g. 0.1 0. 18 0.18 4O KOH/g.).

In the apparatus for carrying out the new method within the adsorptionzone according to FIG. 2, a certain quantity of the granular solids, forexample, of an adsorbent consisting of gamma aluminum oxide, is placedinto each of the above-mentioned containers 1. These containers aresupported on and guided by parallel guide rails 2 in a position exactlyvertically above each other, and are individually retained in place bylocking pawls 3 which only permit a movement in the upward direction.The lowest container 1 is inserted into the lowest locking pawls fromthe side by means of one or more guide rails 4. The uppermost containermay be removed from the apparatus toward one side by means of similarguide rails 4. The liquid, for example, the oil to be refined, issupplied from a storage tank, not shown, through a conduit 5 and acontrol valve 6. The liquid emerges at 7 and is applied upon the layerof solid material in the uppermost container 1. The liquid thenpercolates by gravity through one container after the other and throughthe granular layers of solids therein. After the liquid emerges from thelowest container, it is received by a collecting device 8 which may bedesigned so that the liquid collected therein at different times may beconducted to diflerent storage tanks.

All of the containers 1 of the apparatus are moved at the same time inthe upward direction and against the current of the liquid by means of asuitable elevating mechanism. In the embodiment as illustrated in thedrawings this mechanism consists of a movable system of parallelvertical rods 9' which may be moved upwardly and downwardly. Rods 9carry pickup pawls 10 which are pivotally mounted thereon and are spacedfrom each other at the same distance as locking pawls 3. They are alsoof the same shape and construction as pawls 3 and are adapted to takealong the containers during the upward movement of the elevatingmechanism, while during the downward movement thereof they slidelaterally past the containers which are arrested by the locking pawls.The upward and downward movement of the elevating mechanism is limitedby an upper stop member 11 and a lower stop member 12, respectively, sothat the height of the stroke will always be slightly larger than thevertical distance between the locking pawls, thus always insuring aproper operation of the mechanism. The ele vating mechanism may bedriven by any suitable means; thus, for example, the mechanism of arelatively small apparatus may be operated by hand, while one of alarger apparatus may be operated by a motor through a suitable reductiongear.

FIGS. 4 and 5 illustrate a container for receiving the granular solidsfor use in the apparatus as previously described. The containers may bemade of a shape and size so as to comply with the respectiverequirements of the apparatus. In place of a rectangular shape asillustrated, the containers may also be round. The bottom of eachcontainer consists of a sieve plate 21 which is adapted to support alayer of the granular material of the required thickness. If thematerial is very finegrained, the sieve plate is preferably divided intoa supporting element, 'for example, a perforated metal plate 21, and afilter element 22 which prevents the fine grains from trickling throughplate 21. In special cases, for example, in very large containers, itmay be advisable to provide a solid bottom plate with filter nozzlestherein. Below the bottom plate, the container is slightly inwardlyconical so that the liquid flowing out of it will not flow past therespective lower container but be funneled into it. The upper edge ofeach container has projecting flanges 23 which are designed so as toinsure a proper engagement with pawls 3 and/or 10. If the containershave a round cross-sectional shape, the projecting edge portion ispreferably made so as to extend along the entire periphery so that thecontainer may be inserted in any vertical position into the apparatus.

FIGS. 6 and 7 illustrate a container of a special design and of a roundcross-sectional shape. Sometimes it may happen that channels will formwithin the layer of solids in one container which will oppose the flowof the liquid with a smaller resistance than all other parts of thelayer. Since the liquid always tends to take the path of leastresistance, it will follow these channels so that the layer of solidswithin this container will only exert a minor filtering and adsorbingaction upon the liquid and thus be wasted to a considerable degree. Thismay be avoided according to the invention, as illustrated in FIGS. 6 and7, by mounting a plurality of partitions 29 on the perforated bottom 21of each container 1 so as to divide the container into a plurality ofsmaller sections 30. Partitions 29 may, for example, be of honeycombshape, and their height is preferably made slightly smaller than theheight of the container wall. These partitions divide the layer 31 ofsolids within the container into a plurality of smaller separatequantities. Partitions 29 should be higher than layer 31 so that columnsof liquid 32 of a certain height will form above the layer.Consequently, if a channel should form in one section 30, only theportion of granular material within that section will not exert itsproper filtering and adsorbing action, while all the other portions inthe other sections will not be affected but exert their full action. If,on the other hand, the layer portion in one of the sections 30 shouldbecome clogged, the liquid pressure therein will increase in accordancewith the increasing height of the liquid column 3'2 above that portionso that the interruption will tend to correct itself. The partitions 29are preferably made of such a height that above a certain critical levelthe liquid may run over into the adjacent sections.

The operation of the apparatus according to the in vention proceeds asfollows:

At certain time intervals one container 1 after another, each having alayer of granular material therein, is inserted into the lowest lockingpawls 3. At the same time, the uppermost container is removed from theapparatus. The elevating mechanism is then moved downwardly until thepickup pawls 10 engage under the projecting flanges 23 of eachcontainer. During the following upward movement of the elevatingmechanism, all containers 1 are simultaneously moved upwardly until theyengage into the next-higher locking pawls 3 which hold them in arrestedposition when the elevating mechanism is again moved downwardly. Thisprocedure is repeated at certain time intervals. During the entirelength of the operation, interrupted only during the change ofcontainers, the uppermost container is supplied with liquid which byforce of gravity passes successively through the layers of granularsolids in the individual containers until it emerges from the lowestcontainer and is received by the collecting container 8. The liquid andsolid material thus pass through the apparatus in a countercurrent toeach other and exert a very intensive action upon each other.

The contents of the respective container which is removed from theapparatus at the upper end of the elevating mechanism may be subjectedoutside of the apparatus to a further treatment without being removedfrom the container. The container may then after a suitable time bereinserted into the apparatus at the lower end thereof, either with thesame charge of granular solids or with a new charge.

The upward movement of the elevating mechanism with all containers mayproceed at any desired speed. Immediately after the change ofcontainers, they may be lifted within a period of a few seconds which isthen followed by a longer period of rest. The upward movement may,however, also be carried out within a longer period between twosuccessive container changes. This will be of advantage particularly inlarger appartus since it will permit a considerable saving in operatingpower.

Even though this invention has been illustrated and described withreference to the preferred embodiments thereof, it should be understoodthat it is in no way limited to the details of such embodiments, but iscapable of numerous modifications within the scope of the appendedclaims.

'The invention having now been fully disclosed, it is claimed that:

1. An apparatus for the refining of a liquid petroleum productincluding: an elongated generally vertically disposed zone whereinrefining of the petroleum is effected by adsorption; a plurality ofindividual open-top, foraminous-bottom container having solid side wallsfor confining a granular adsorbent material while it is conductedthrough the refining zone; a peripheral flange on each of saidcontainers at its upper end; means for introducing said container means,one at a time, into the lowermost portion of the refining zone; meansfor elevating said containers comprising a supporting frame suspended insaid refining zone and including a plurality of downwardly extendingrods depending from said frame for substantially the length of therefining zone; pawls pivotally mounted on said rods for engaging saidperipheral flange and for simultaneously advancing each of the containermeans stepwise upwardly through the refining zone; means forintermittently reciprocating said rods vertically; means for limitingthe travel of said frame and said rods to slightly more than the heightof one container, at each step; means for admitting a liquid to berefined into the uppermost of said opentop, foraminous bottomcontainers; means for withdrawing said uppermost container from therefining Zone; means for withdrawing refined liquid product from thebottom of the refining Zone; and vertically extending guide railssecured to an external support adjacent to said refining zone formaintaining the containers in vertical alignment.

2. The apparatus of claim 1 wherein the individual containers compriseopen-top foraminous bottom vessels divided by solid, vertical partitionwalls into a plurality of separate compartments, each adapted to receivesolid absorbent, the height of the partition walls being slightly lessthan the height of the solid peripheral walls.

References Cited in the file of this patent UNITED STATES PATENTS2,323,830 McMillan July 6, 1943 2,487,574 Meng Nov. 8, 1949 2,509,486Danforth May 30, 1950 2,548,966 Gilmore Apr. 17, 1951 2,564,717 OlsenAug. 21, 1951 2,731,149 Findlay Jan. 17, 1956 2,771,407 Penick Nov. 20,1956 2,781,301 Payne Feb. 12, 1957

1. AN APPARATUS FOR THE REFINING OF A LIQUID PETROLEUM PRODUCTINCLUDING: AN ELONGATED GENERALLY VERTICALLY DISPOSED ZONE WHEREINREFINING OF THE PETROLEUM IS EFFECTED BY ADSORPTION, A PLURALITY OFINDIVIDUAL OPEN-TOP, FORAMINOUS-BOTTOM CONTAINER HAVING SOLID SIDE WALLSFOR CONFINING A GRANULAR ADSORBENT MATERIAL WHILE IT IS CONDUCTEDTHROUGH THE REFINING ZONE, A PERIPHERAL FLANGE ON EACH OF SAIDCONTAINERS AT ITS UPPER END, MEANS FOR INTRODUCING SAID CONTAINER MEANS,ONE AT A TIME, INTO THE LOWERMOST PORTION OF THE REFINING ZONE, MEANSFOR ELEVATING SAID CONTAINERS COMPRISING A SUPPORTING FRAME SUSPENDED INSAID REFINING ZONE AND INCLUDING A PLURALITY OF DOWNWARDLY EXTENDINGRODS DEPENDING FROM SAID FRAME FOR SUBSTANTIALLY THE LENGTH OF THEREFINING ZONE, PAWLS PIVOTALLY MOUNTED ON SAID RODS FOR ENGAGING SAIDPERIPHERAL FLANGE AND FOR SIMULTANEOUSLY ADVANCING EACH OF THE CONTAINERMEANS STEPWISE UPWARDLY THROUGH THE REFINING ZONE, MEANS FORINTERMITTENTLY RECIPROCATING SAID RODS VERTICALLY, MEANS FOR LIMITINGTHE TRAVEL OF SAID FRAME AND SAID RODS TO SLIGHTLY MORE THAN THE HEIGHTOF ONE CONTAINER, AT EACH STEP, MEANS FOR ADMITTING A LIQUID TO BEREFINED INTO THE UPPERMOST OF SAID OPEN-TOP, FORAMINOUS BOTTOMCONTAINERS, MEANS FOR WITHDRAWING SAID UPPERMOST CONTAINER FROM THEREFINING ZONE, MEANS FOR WITHDRAWING REFINED LIQUID PRODUCT FROM THEBOTTOM OF THE REFINING ZONE, AND VERTICALLY EXTENDING GUIDE RAILSSECURED TO AN EXTERNAL SUPPORT ADJACENT TO SAID REFINING ZONE FORMAINTAINING THE CONTAINERS IN VERTICAL ALIGNMENT.